1. Field of the Invention
The present invention relates to a direct-fluid-supply writing device. More particularly, the present invention relates to a direct-fluid-supply writing device incorporating an ink occuluding member disposed between a pen point and an ink tank and made of a porous material.
Incidentally, it should be noted that xe2x80x9cfrontxe2x80x9d is a direction toward the pen point and the xe2x80x9crearxe2x80x9d is a direction toward the ink tank.
2. Description of the Related Art
Conventionally, a direct-fluid-supply writing device has been known, which incorporates an ink occuluding member made of a porous material and serving as an ink keeping member for temporarily keeping overflowing ink when the internal pressure of an ink tank has been raised (refer to, for example, JA-B-37-12939U and JP-W-6-510491).
In JA-B-37-12939U, a fountain pen type felt pen has been disclosed, which incorporates a pipe for ink which accommodates an ink reservoir (corresponding to an ink tank according to the present invention); a filled chamber (corresponding to an ink occuluding member according to the present invention) formed in front of the ink reservoir and filled with waste felt or cotton; and a seat plate (corresponding to a partition wall according to the present invention) arranged to partition the filled chamber and the ink reservoir from each other and provided with small apertures (corresponding to communication holes according to the present invention), wherein an elongated felt member (corresponding to an ink inducing member according to the present invention) subjected to a resin process is inserted into the seat plate and the filled chamber.
The direct-fluid-supply writing device disclosed in JA-B-37-12939U is a direct-fluid-supply writing device, in which the ink tank and the pen point are directly connected to each other through the ink inducing member without passage through the ink occuluding member. Therefore, a satisfactory ink discharge characteristic from the pen point can be obtained as compared with a structure that the ink inducing member does not penetrate the ink occuluding member. However, the realized ink discharge characteristic is unsatisfactory in consideration of satisfactorily preventing leakage of ink.
The reason for this will now be described. The sizes of the voids in the capillary structure of the ink occuluding member cannot easily be uniformed in spite of an attempt to uniform the sizes of the voids. Therefore, the sizes of the voids considerably disperse. In particular, voids in the capillary structure having large sizes cannot serve as the temporary ink keeping portions. The existence of the large size voids in the capillary structure causes the overall ink keeping function of the ink occuluding member to deteriorate, causing a problem of ink leakage to easily take place. To effectively form ink keeping portions in the overall body of the ink occuluding member, the sizes of the voids in the capillary structure must previously be reduced (that is, the overall porous structure must have a dense structure).
Therefore, the direct-fluid-supply writing device disclosed in JA-B-37-12939U has small-size voids in the capillary structure of the ink occuluding member to realize a satisfactory ink leakage prevention characteristic. Therefore, ink can reliably be kept in the voids in the capillary structure of the ink occuluding member. On the other hand, air cannot smoothly be introduced into the ink tank, the pressure of which has been reduced. As a result, the ink discharge characteristic from the pen point deteriorates, causing written characters become pale and blurred.
The direct-fluid-supply writing device disclosed in JA-B-37-12939U incorporates the ink occuluding member having uniform capillary attraction. Therefore, when the device is preserved for a long time in a state where the pen point faces downwards, ink is easily concentrated in the front portion of the ink occuluding member. Thus, there is apprehension that ink outwards leaks owing to shock caused when the device is dropped or when the cap is removed. Ink concentrated to the front portion of the ink occuluding member cannot be returned into the ink tank even after the pressure in the ink tank has been reduced owing to consumption of ink. That is, ink is easily accumulated in the front portion of the ink occuluding member. Thus, there is apprehension that ink leaks from the pen point portion.
In JP-W-6-510491, a direct-fluid-supply writing device has been disclosed which has a structure that the capillary supply pipe (corresponding to the ink inducing member according to the present invention) and a capillary solution accumulating container (corresponding to the ink occuluding member according to the present invention) are brought into direct contact with each other. Moreover, the capillary supply pipe is engaged to an opening of a partition wall (corresponding to a partition wall according to the present invention) to close the opening. In addition, the capillary supply pipe engaged to the opening form voids (corresponding to the communication hole according to the present invention) having larger capillary attraction than that of the capillary solution accumulating container to cause an action of exchanging air and ink to be performed.
In general, the communication hole (the void) controls passage of ink and air between the ink tank and the ink occuluding member owing to its sizes (the capillary attraction). Therefore, an excellent dimension accuracy is required to permit communication of air and ink.
If the communication hole has an excessively large size, the capillary attraction is reduced. When the pressure in the ink tank has been reduced, smooth return of ink from the ink occuluding member to the ink tank is inhibited. As a result, outer air is introduced into the ink tank in a state where ink remains in the ink occuluding member. Therefore, the state in the ink tank in which the pressure has been reduced is canceled. When the pressure in the ink tank has been raised, the ink keeping portion cannot sufficiently keep leaked ink. Thus, there is apprehension that ink leaks from the pen point portion.
If the size of the communication hole is too small, the capillary attraction of the communication hole is enlarged. Thus, introduction of air into the ink tank having the reduced pressure is inhibited and, therefore, smooth exchange between ink and air is inhibited. As a result, the reduced-pressure state in the ink tank cannot be canceled. Hence it follows that the quantity of discharged ink from the pen point is gradually reduced from start of consumption of ink. Thus, written characters become pale and blurred.
It can be considered that the communication hole maintains the ink head pressure (density of inkxc3x97gravitational accelerationxc3x97height from the leading end of the pen point to the communication hole) owing to its capillary attraction. If the capillary attraction is insufficiently small (that is, if the sizes of voids are large), the capillary attraction is insufficient to maintain the ink head pressure. As a result, ink in the front portion of the communication hole moves downwards when the pen point faces downwards. Thus, there is apprehension that ink leaks from the pen point.
Therefore, the direct-fluid-supply writing device disclosed in JP-W-6-510491 and incorporating the ink inducing member made of the porous material, such as fibers, encounters great dispersion of sizes of the plural voids in the ink inducing member. Thus, the largest void serves as the communication hole according to the present invention which permit air blow.
To make the size of the largest void serving as the communication hole to be small so as to prevent the problem of leakage of ink from the pen point portion caused from retention of ink in the ink occuluding member, the sizes of the voids in the capillary structure of the ink inducing member in the opened portion must considerably be reduced in consideration of dispersion of the sizes of the voids. As a result, the capillary attraction of the communication hole is enlarged excessively to hardly introduce outer air into the ink tank having the reduced pressure. Thus, the state of pressure reduction in the ink tank cannot sufficiently be canceled, causing the ink discharge characteristic from the pen point to gradually deteriorate from start of ink consumption.
The direct-fluid-supply writing device disclosed in JP-W-6-510491 incorporates only one communication hole formed in the rear of the ink occuluding member. Therefore, the communication hole must have considerably large capillary attraction in consideration of the relatively high ink head pressure from the pen point. As a result, smooth ink discharge characteristic from the pen point cannot easily be obtained similarly to the above-mentioned structure.
Moreover, the ink inducing member of the direct-fluid-supply writing device disclosed in each of JP-B-37-12939 and JP-W-6-510491 is made of the porous material, such as fibers. Therefore, the overall body of the ink inducing member has great capillary attraction. Since the distance from the communication hole to the pen point is long, great resistance arises when ink passes. Thus, ink in a large quantity cannot quickly be supplied to the pen point. As a result, written characters become pale and blurred.
What is worse, the direct-fluid-supply writing device disclosed in each of JP-B-37-12939 and JP-W-6-510491 encounters insufficient supply of ink from the ink tank to the pen point when the pen point faces upwards in a case where, for example, writing on a writing board or the like is performed or when the pen point faces horizontally (when the body of the device is in a horizontal state). Thus, written characters become pale and blurred.
An object of the present invention is to provide a direct-fluid-supply writing device which is capable of simultaneously realizing a satisfactory ink discharge characteristic from the pen point and sufficient prevention of ink leakage from the pen point portion. Another object of the present invention is to provide a direct-fluid-supply writing device which is capable of continuously discharging ink even if the pen point faces upwards or horizontally.
(a) According to a first aspect of the present invention, there is provided a direct-fluid-supply writing device 1 comprising: an ink occuluding member 5 disposed between a pen point 61 and an ink tank 21 and made of a porous material; a partition wall 4 disposed between the ink occuluding member 5 and the ink tank 21; and communication holes 8 and 9 for controlling exchange of ink and air between the ink occuluding member 5 and the ink tank 21, wherein the partition wall 4 is extended in the lengthwise direction so that a first communication hole 8 connected to the front portion of the ink occuluding member 5 provided with the pen point 61 is formed in the front portion of the partition wall 4 and a second communication hole 9 connected to the rear portion of the ink occuluding member 5 is formed in the rear portion of the partition wall 4.
Improvement in Ink Discharge Characteristic
The foregoing structure enables at least the distance from the first communication hole 8 to the leading end of the pen point 61 to be shortened. Therefore, the ink head pressure of the first communication hole 8 can be reduced. As a result, the capillary attraction of the first communication hole 8 can be reduced as compared with that of the conventional structure. That is, the first communication hole 8 is able to have voids, the size of which can relatively be enlarged.
Therefore, the distance from the first communication hole 8 and the leading end of the pen point 61 can be shortened, causing the resistance of ink which passes through the ink movement passage from the first communication hole 8 to the pen point 61 can be lowered. Moreover, the sizes of voids in the first communication hole 8 can be enlarged. Therefore, the resistance of ink which passes through the first communication hole 8 can be lowered. Hence it follows that ink can smoothly be moved from the ink tank 21 to the pen point 61. As a result, interruption of written characters and a problem that written characters become pale and blurred can be prevented.
Since the sizes of voids of the first communication hole 8 can relatively be reduced, excellent dimension accuracy is not required when a manufacturing process is performed. Therefore, the manufacturing process can easily be performed.
Prevention of Ink Leakage
Ink is sometimes concentrated in the front portion of the ink occuluding member 5 owing to preservation of the direct-fluid-supply writing device for a long time in a state where the pen point faces downwards. However, ink concentrated in the front portion of the ink occuluding member 5 can smoothly be returned to the inside portion of the ink tank 21 through the first communication hole 8 after the pressure in the ink tank 21 has been reduced owing to consumption of ink. Therefore, ink does not remain in the front portion of the ink occuluding member 5. That is, leakage of ink from the pen point 61 can be prevented.
Moreover, the front portion of the ink occuluding member 5 adjacent to the first communication hole 8 and the rear portion of the ink occuluding member 5 adjacent to the second communication hole 9 serve as the first ink keeping portion and the second ink keeping portion, respectively. Therefore, the ink keeping function of the ink occuluding member 5 can effectively be exhibited in the portions across the ink occuluding member 5. Therefore, the characteristic for preventing leakage of ink from the pen point 61 can furthermore be improved.
In a second aspect of the present invention, it is preferable that the direct-fluid-supply writing device 1 according to the first aspect has a structure that an ink inducing member 6 connected to the pen point 61 and made of a porous material is inserted into the front portion of the partition wall 4, and the outer surface of the ink inducing member 6 is brought into contact with the inner surface of the front portion of the ink occuluding member 5.
The ink inducing member 6 enables ink to quickly and smoothly be supplied from the ink tank 21 to the pen point 61 and the front portion of the ink occuluding member 5. Moreover, ink kept in the front portion of the ink occuluding member 5 can quickly and smoothly be returned to the ink tank 21. Thus, the ink discharge characteristic and the characteristic for preventing leakage of ink can furthermore be improved.
In a third aspect of the present invention, it is preferable that the direct-fluid-supply writing device 1 according to the first or second aspect has a structure that the partition wall 4 is constituted by a cylindrical portion 41 inserted into the ink occuluding member 5 and a flange 42 continuously formed from the rear end of the cylindrical portion 41 and brought into contact with the rear end of the ink occuluding member 5. Moreover, the first communication hole 8 for causing the front portion of the ink occuluding member 5 provided with the pen point 61 and the ink tank 21 to communicate with each other is formed in the front end of the cylindrical portion 41. In addition, the second communication hole 9 for causing the rear end of the ink occuluding member 5 and the ink tank 21 to communicate with each other is formed in the flange 42.
Since the partition wall 4 is constituted by the cylindrical portion 41 and the flange 42, the first communication hole 8 and the second communication hole 9 of the direct-fluid-supply writing device 1 according to the first or second aspect can effectively be formed.
In a fourth aspect of the present invention, it is preferable that the direct-fluid-supply writing device 1 according to the first aspect is structured such that compressing portions 51 and 52 for making capillary attraction of the ink occuluding member 5 to be larger than capillary attraction of the other portions is provided for a portion adjacent to the first communication hole 8 of the ink occuluding member 5 and/or a portion adjacent to the second communication hole 9 of the ink occuluding member 5.
The compressing portions 51 and 52 enable ink to always be concentrated in the vicinity of the communication holes 8 and 9 of the ink occuluding member 5 even if the pen point 61 is caused to face downwards. Thus, an ink barrier for preventing introduction of air occurring when the pressure in the ink tank 21 has been reduced can be formed in the foregoing portion. As a result, continuous return of ink from the ink occuluding member 5 to the ink tank 21 can be performed without including any air when the pressure in the ink tank 21 has been reduced.
It is preferable that the compressing portion 52 is formed adjacent to the second communication hole 9. The ink head pressure from the leading end of the pen point 61 is higher in the portion adjacent to the second communication hole 9 as compared with the ink head pressure in the void of the first communication hole 8. Therefore, ink can easily be moved in the downward direction. To keep ink in a sufficiently large quantity to prevent introduction of air, it is effective to form the compressing portion 52.
In a fifth aspect of the present invention, it is preferable that the direct-fluid-supply writing device 1 has a structure that an ink keeping member 22 connected to the rear end of the ink inducing member 6 and made of a porous material is disposed in the rear of the first communication hole 8.
As a result, when the ink accumulated in the ink tank 21 and the ink inducing member 6 are disconnected in a state where the pen point faces upwards or horizontally, the ink keeping member 22 connected to the ink inducing member 6 is disposed adjacent to the ink tank 21 of the partition wall 4. As a result, ink kept in the ink keeping member 22 can be supplied to the pen point 61 through the ink inducing member 6. Therefore, interruption of written characters and blur of the same can be prevented. The foregoing function is effective when writing on a standing writing board, such as a white board, is performed.